import java.util.Date;//导包
import java.math.*;
public class demo {
    public static void main(String[] args) {
        student s = new student("张三",15);
        s.eat();
        s.setName("李四");
        System.out.println(s.getName());
        s.eat();
       int a = 9;
        System.out.println(Math.sqrt(a));
        s.classRoom = "04092202";
        System.out.println(s.classRoom);
        System.out.println(s);
    }
}
